2. analog
  3. 1215361521

Upgrade for users of 1/2" mylar belt

This thread will be of interest to Galibier, Redpoint and Teres belt drive TT owners, or anyone using or thinking of using a drive belt made from 1/2" mylar. The belt material of choice on these tables for several years has been the silver holographic mylar streamers from sources linked on the Teres and Galibier websites. This outperforms everything else we've tried but like anything it's not perfect - and we've now found something better.

One of the silver holographic mylar's assets can also become a liability. That metallic layer, when new, gives the belt exceptional "grip" on the platter and motor capstan. Minimal slippage on transients is one reason the material works so well. Unfortunately, that layer can wear over time, leaving a silvery gray residue and allowing performance to deteriorate. The only solution has been a good cleaning and a new belt. No big deal, but if there was a better or more stable belt Paul and I wanted to find it.

I'll spare you a recounting of our many experiments and jump to the good news: thanks to (yet another) brainstorm by my resident genius/partner, we've developed a belt that both performs better and lasts longer. I've held off posting until we were sure, but after 4 months of steady use Paul’s idea is still working perfectly. The only negative is that making this new belt takes an hour or more of work spread over two days, but to us it's worth the effort.

HOW TO MAKE ONE

1. Cut a length of the silver holographic mylar tape sufficient for your TT, plus 3-4" extra.

2. Remove the silver metallic coating off the backside of the mylar. Paul used an acid etching cream popular with stained glass hobbyists to dissolve the metal - safe, quick and easy (use skin and eye protection).

3. Rinse thoroughly under running water, inspect to make sure you got all the silver off, wipe and hang to dry overnight.

4. Splice as normal to make a TT belt, making sure you tape on the OUTSIDE (which will be smoother than the now bare inside).

5. As always, the best splicing technique is to overlap the ends and cut on a 30-40 degree angle. Apply 1” video splicing tape (*not* tabs) across the belt at the *same* angle and trim away the excess.


WHY IT PERFORMS BETTER

Unlike any plain mylar ribbon you could easily buy, the silver holographic streamer has an ultra fine texture embossed on the back side of the *mylar* during manufacturing (*before* the metallic backing is applied). Once the silver layer is applied you can't see this texture, but that's what diffracts light like a million tiny prisms to produce the shimmery rainbow effect. Stripping the metal backing away exposes this texture, which becomes the contact surface of your new belt.

Paul realized this texture must exist and then hypothesized that using it for the working side of a TT belt might provide more “grip” on the platter rim and motor capstan than either plain mylar (which is extremely smooth) or the metallic backing. He was right. This belt produces more lifelike dynamics, both macro- and micro-, than even a brand new silver holographic belt - which heretofore was the best.

WHY IT LASTS LONGER

Removing the metallic backing exposes bare mylar, which is much sturdier than that fine layer of metal. Under normal use and assuming no accidents, one of these belts should last many, many months, perhaps years, while delivering consistent performance. Ours is going into its fifth month with few visible and no audible signs of wear.

Different motor capstan materials might interact with this belt differently, but I urge anyone with a compatible table to give this a try. Like all our favorite little tweaks, we'd find it hard to go back.

A FEW TIPS

1. Clean any silver/grey residue from your old belt off the motor capstan and platter before mounting the new belt.

2. As many of us have learned, the more inelastic the belt, the more critical motor leveling becomes. That is truer than ever with this new belt. Getting the motor set just right is touchy. Take care that your new belt is riding level in the center of the capstan before you start to play. You don't want it sliding up or down and mangling itself.

3. Motor distancing is also more critical than ever. Since this belt will not slip *or* stretch, tension must be perfect. The right amount is just shy of the tension that would tilt the motor off its feet.

4. Depending on your climate, the belt can build up static potential during use. Not enough to spark, but more than enough to attract airborne dust. I dust the belt's inside with my CF brush after each side before stopping the platter.

5. With this or any belt, always start your platter spinning with a helping push. Just pressing the motor's ON button creates lots of belt-wearing friction as the rapidly spinning motor tries to drag that heavy platter up to speed.

It all sounds like a pain, and it is! But the sonic and longevity results are worth the effort.

Cheers,
Doug
dougdeacon
george_a
34 posts
 
I am very interested in trying Kapton belts.

I telephoned A2Z as listed on the Galibier site. They require a $150 setup charge and $800 for 10 belts. This was for seamless 2mil Kapton. They do not do 1mil Kapton. They said making true seamless belts is difficult, not to be confused with welding or splicing, which will leave a feelable join.

I telephoned Blue Lake but have not been able to get past the answering machine, so I requested a quote via email. Pulsar mentions his cost at Blue Lake was $50 a belt, but Galibier states they require a large minimum order.

I also requested a quote via email from Belt Corp.

Would love to hear from Pulsar or anyone else that has had experience ordering seamless Kapton belts.

BTW AJ Conti (Basis turntables) has some interesting information regarding his quest for the ultimate belt. He ended up grinding his own rubber flat belts to a thickness of 0.015" and a uniformity of 0.0001". He believes uniformity is the most important speed parameter and thinness is desirable for isolation. Sounds like Kapton should be even better.
thom_at_galibier_design's avatar
thom_at_galibier_design
724 posts
 
Hi all,

I've been too engaged with the Eiger to look into this. I suspect that these companies thought they were doing a one-off and made belts for a few folks like Palasar. Then, they started receiving a flood of requests and realized that these "ones-ies" were a distraction from their main business.

I'll look into quantity pricing in the near future. BTW, you want at least .002" thick. .002" works well, but even as durable as Kapton is (relative to Mylar), I'm curious about .003" thick belts.

I'd be tempted to reduce the width to keep the overall mass the same (energy transfer to the platter) - reducing it to perhaps .375" wide. With my wide pulleys (approx. 1.3" in diameter), there's plenty of pulley surface for traction - slippage reduction.

I'm not sure how this .125" reduction would work with a skinny pulley - the sort we used to use at Galibier. I'd be tempted to stay at .500" wide if I were running a skinny pulley.

AJ has some excellent information in his treatise on belts. Of course, he's looking to optimize what I view as a lossy system - a stretchy belt.

Now, if everyone made the same product, it would be a boring world, wouldn't it?

Cheers,
Thom @ Galibier
dougdeacon OP
3,338 posts
 
Thom,

I also experimented with thicker mylar belts (probably described it somewhere above). On my Teres, a .003" belt slipped badly. As thinner mylar belts did not do this, I attributed the slipping to the thick belt being too rigid to maintain contact as it attempted to make the tight turn around the capstan.

For torque transfer, the optimal setup is probably subject to the so-called Capstan equation. Note that this equation assumes that the belt is inelastic and not overly rigid. Both of these considerations have been been (and are still being) discussed and developed by you and other participants on this thread.

Of course this does not address noise transfer. As you noted, the requirements of maximizing torque transfer while minimizing noise transfer are largely contradictory. The optimal solution will always vary with the characteristics of the motor and turntable.

BTW, neither the Galibier motor nor any other TT motor uses a "pulley". By design, pulleys minimize torque transfer (ideally to zero). Attaching a pulley to a TT motor would result in a platter rotational speed fairly close to zero.

Turntables use "powered capstans".

Doug
thom_at_galibier_design's avatar
thom_at_galibier_design
724 posts
 
Hi Doug,

Pulley/Sheave/Capstan. Pulley seems to be the term most people can relate to, but I certainly get your point.

I can see where (with a narrow pulley), the stiffer .003 Mylar could potentially be problematic. We've gone to 1.360" diameter pulleys (partly for traction purposes), so I'm inclined to revisit this area.

Yes, energy transfer is very real, and the woven fabric belts we started with (initially used with our new motor drive) proved to transmit more noise to the platter than the "plastic" belts (Mylar and Kapton).

To a certain extent, this belt thickness question moves us along a continuum - from rubber belts, to rigid belts, to rim and direct drive. As you move along this continuum, noise increases and the question we can only answer for ourselves is "where do I stop along this continuum?" (assuming that speed stability and noise are inversely related.

Cheers,
Thom @ Galibier
thom_at_galibier_design's avatar
thom_at_galibier_design
724 posts
 
I just heard back from Dean at Blue Lake Products & they've developed a pricing model for small quantities.

I placed the direct link to their new turntable belt page on my Support/Belts page for your permanent reference: http://galibierdesign.com/supt_belts.html.

They will sell single belts. The process is labor intensive and large quantities won't yield me any significant discounts, so you're best ordering directly from them.

They will manufacture different thicknesses, and with my much wider pulleys, I still intend to experiment with .003" thick material.

Cheers,
Thom@Galibier
More to discover